Seal for fans



Aug. 24, 1948. D M OR 2,447,957

SEAL FOR FANS Filed Dec. 29, 1945 I l N V E NTO R fioberf 0 Moore.

ATTORNEY$ Patented Aug. 24, 1948 UNITED STATES PATENT; OFFICE 2,447,957 a SEAL FOR FANS a Robert D. Moore, Kansas City, Mot, assignor to The Moore Company, Kansas City, Mo., a cor-, poration of Missouri a Application December 29, 1945, Serial N0. 638,189

4 claims, (Cl. 230-420) This invention relates to fans and particularly to a seal for closing space between the tips of the blades of a fan and the flow control ring in which the blades turn. In fans of relatively large diameter it has been impossible to establish and maintain close tolerance between the tips of the .blades and the surrounding ring because of difficulty in maintaining roundness of the ring and concentricity of the fan. Consequently, such fans are constructed with sufficient clearance to allow ring is made of larger diameter to provide space for adequate clearance of the blades so as to avoid H at the tips of the blades.v This space allows striking thereof against any part of the ring. operation of the blades, but;it results in'loss in Therefore, considerable'efliciency' is lost by eddy efficiency caused by leakage of pressure at thetips currents at the tips of the blades, that is, the air of the blades when vthefan is in operation; propelled by the blades spills backwardly through In accordance with the present invention, I such space. i V v have provided a seal for closing this space which It is the purpose of the present invention to is adapted to be moved into. substantial contact provide a seal for maintaining close tolerance at with the tips of the blades and adjusted incidenthe tips of the blades regardless of eccentric lotal to turning of fan on its rotational axis so that cation of the fan or any out-of-roundness of the th spacev is closed circumferentially of the fan c0ntro1 ring. regardless ofexcentricity or any irregularities in A further object of the invention is to provide the shape of the ring. l v a seal that can be maintained throughout the life In carrying Out the invention, provide the of the fan even though the shape of the ring or Web 6 of the ringwith a sealing member. Inthe eccentric relationship between the fan and conform of the invention illustrated in Fig. l, the trol ring may change. sealing member comprises a circular band, 12 In accomplishing these and other objects of formed of a tractableor ductile material having the invention, I have provided improved struca relatively low elastic limit such as coppen lead ture, the preferred form of which is illustrated in and'the like to permit ready. formation thereof the accompanying drawing wherein: to the path of the fan blade tips. Theband [2 Fig. 1 is a vertical section through a fan unit is applied to the ring 4'- before insertion of a fan equipped with a seal constructed in accordance I and has the side edges l3 and. 14 thereof sewith the present invention. cured adjacent the front and rear. sides of the Fig. 2 is a fragmentary perspective section of ring to produce an inward bulge If: as shown in the fan unit. Fig. 1, care being taken that the inner diameter Fig. 3 is a similar perspective section of a of the bulge is less than the diameter of the fan modified form of seal. at the tips of the blades. Therefore, when the Fig. 4 is a similar section of a further modified fan is inserted, the tips of the blades are contact.- form of seal. ing the inward bulge of the band and as the Referring more in detail to the drawing: to fan is rotated slowly by hand, a portion of the l designates a fan which may be of large diambulge will be pushed outwardly by the tips ll) of eter such as a fan used in wind tunnels, induced the blades and give the slight clearance necessary or forced draft cooling towers, air conditioning for rotation of the fan blades. By reason of the systems and the like. The fan includes a hub relatively low elastic limit of the material from 2 and radially arranged bladesSfixed thereto and which the band is constructed, the band will adapted to rotate within a flow control ring or maintain its imparted shape and when the fan frame member 4. The fan is mounted on a shaft is placed in operation, the tips of the blades will 5 to which the hub 2 is attached, the hub 2 being rotate freely within the band with a minimum of supported as near as possible in concentric reclearance the'rebetween. Consequently, the lation with the ring 4. In the present illustrablades of the fan are effective throughout the ention, the ring 4 includes a web portion 6 encircling tire length thereof and eddy currents are elimithe fan and may be of cylindrical formation; nated at the tips of the blades which ordinarily however, the ring may be coned or otherwise reduce efilciency of a fan. In order to facilitate formed without departing from the spirit of the bulging of the ring into position to be contacted invention. The sides of the ring may be reinby the tips,'the ring 4 may be provided with an forced by circumferential flanges which the ring is attached to which it is used.

As above stated, it is diflicultto .form such rings in a perfect circle, and even if the ring is substantially a perfect circle, it is difiicult to maintain the shape thereof and concentricity of the fan. Therefore, to prevent striking of the tips I!) of the blades on any part of the ring, the

l andj 8 with the structure in 3 externally threaded tubular fitting I6 to which a supply pipe (not shown) may be connected for introducing a pressure medium into the space I I so as to move the bulge portion I5 into contact with the tips of the fan blades.

The form of the invention shown in Fig. 1 is satisfactory for the purpose; however, it is possible that-iduring operation or :work on' the fan, the band may be deformed, in which case it would be diflicult to return the band into its original position relative to the fan blades because of inaccessibilit to the space I I without removal of the band. To avoid this difficulty, the sealing band may be attached to a control ring I8 at one edge I9 thereof as shown inFigI-"B. The opposite edge of the sealing band curves inwardly as at 20 and then flares outwardly .in a rounding curve as at 2I at the discharge side of the fan; In this case, the fan blades are offset fromthe supporting ring I8 as shown so that the sealing =bandforms a partof the -controlring. When the fan'is to be placed in operation, the seating band is pressed inwardly so that it is in-position to be contacted-by the tips-of-v the blades. Then, upon hand turning er the fan, aportion: of the 'ring is pushed outwardly by theblade tips to provide sufiicient clearance ior rotation =of -the fan. Should the fan become out of centeror theisealing band 'become' distorted ioran reason, the sealing band-mayb returned to contacting relationwith the tips or the fan blades by:=app1ying pressure on theexterior side-"of the projecting portion of the band.

In theform of invention shown in-"Eig. '4, the sealing band 22' is attached ="alon'g on edge. 23 tothe controlring '22, while the'opposite edge 24 "terminates entirely within the limit-50f :the control ring and is --left tree so i :that: sufficient 'spacelfi isprovided between the-'controliring and band'to' permit insertion 'of a toolror other means for pressingthe sealing portion-26 oithe band into contact with thetips of the blades.

.From' the foregoing 'it is'obviousf-thattl have provided a seal for i ans whereby substantially close tolerance can "be established and easily maintained at the tips'of the fan blades.

What'I claim and-desire:tosecure by Letters Patent is:

"1. In combination "with a ian having blades rotatable within" an annular air control. member encircling the fan blades at the tips-thereof space closing means carried by thecontrol member in encircling" relation with' the i fan a-nd' in initial contact 'w'ith'the' tipsor said bladesy said space closing-means beingcomposed'o'fan easily tractahis material for sufiicient displacementby the fan blades to permit free rotation of i the "-fan and having low" elasticity to maintain 'sacl'd-rrdisplaced posit-ion for substantially closing the space between the tips of the fan blades and the control member.

2. In combination with a fan having blades rotatable within an annular air control member encircling the fan blades at the tips thereof, an annular band having at least one side edge fixed .to' the" control member and having an inwardly bulging portioninitial'ly *contacting'the tips of the fan blades, said band being composed of an easily tractable sheet material for suificient outward displacement of said inwardly bulging portion to clear said blades upon rotation of the fan, and said material being of low elasticity to maintain said displaced position during continued operation of the fan.

3. In combination with a fan having fan blades rotatabl within an annular air control member encircling the fan blades at the tips thereof, an annular band encircling the fan and having side edges fixed to the controlmember with the intermediate portion bulged inwardly into. initial: contact with the tips of the fan :bladesssaidr band being composed of an easily tractable material having'low elasticity to'bedispiaced by 'said blades uponini-tial rotation of said 'fanwan'd". to maintain said displaced position :duri'ngrcontin- 'ued operation of the fan.

4. In combination with a fan'having fan" blades rotatable within an: annular: air" control member encircling the fan bladesat thetipsthereoLwa band encircling thefan. and having sideedges fixed to the control membenimeans for introducing a pressure medium between =ltheattached edges of the band and said-control member for bulging the intermediate portion of said band inwardly into contact 'w'l'th'the tips of the fan blades, said band being composed of an'easily tractable material formable under the pressure medium and having-low elasticity to be displaced by said blades upon initial rotation oi said ian and to maintain said displacement during continued operation of the fan.

ROBERT D. MOORE.

REFERENCES CITED The following references are of record-in the file of thispatent:

UNITED' STATES PATENTS Number Name Date 2,054,142 Sharp Sept. 15, 1-936 2,382,839 Wuensch Aug/14, 1945 FOREIGN PATENTS Number Country Date 42 ,680 Germany Feb. 11, 1926 

